A few days ago, a Neowin reader xillibit posted a query on our forum since they were curious to know why they were getting a 0xc1900101 error when trying to update to Windows 11 24H2. This caught our attention and we wondered if more people were getting this error.
Turns out, the 0xc1900101 error seems to be pretty widespread,with various users experiencing the issue all throughout 24H2 Insider testing as well as final release.
In fact, the bug popped up in the very first version 24H2 Insider build itself back in February earlier this year with build 26052. And it has done so time and again, with more recent incidents surfacing back in September, though Microsoft again confirmed it has been fixed earlier this month in build 27718. It wrote:
Fixed an issue which was causing some Insiders to experience a hang at the boot screen and their PC to roll back with error 0xC1900101 when trying to upgrade to the previous flight.
The issue was also reported on the Feedback Hub, one such instance titled "My PC rolled back when attempting to install the latest Windows Update (error code 0xc1900101)" which was subsequently upvoted over 8000 times, across two entries.
Microsoft has also responded to these queries stating that the problem is a generic error code that is displayed when an update fails and it is rolled back. It writes:
.. error code 0xc1900101 is a generic error displayed when an update fails and rolls back for some reason. This is an area we monitor closely and can have different root causes depending on which build you were attempting to upgrade to and your setup. If you were attempting to update to a previous Insider build, please try the latest one, as it may address your issue.
If you"re interested in understanding more about what may have been the cause of your specific issue, the update logs can be informative: https://docs.microsoft.com/windows/deployment/upgrade/log-files.
Essentially, Microsoft is telling users to try again or try harder in case they come across the issue.
Elsewhere in a support article, the company has published details about the error and appears to be a bit more helpful than the above response. The company notes this can be a result of a "driver error." It says:
An error that begins with 0xC1900101 is usually a driver error. If you see any of these error codes, try the following steps first to fix the problem. If these steps don’t work, see Resolve Windows upgrade errors for more detailed technical info.
- 0xC1900101 - 0x2000c
- 0xC1900101 - 0x20017
- 0xC1900101 - 0x30018
- 0xC1900101 - 0x3000D
- 0xC1900101 - 0x4000D
- 0xC1900101 - 0x40017
On a related note, in case you are not being offered the Windows 11 24H2 Update on your PC, you can try force-triggering it using this Group Policy or Registry trick.